Fix dependency of Image headers on StridedArrayView.

doc/changelog.dox

@@ -220,6 +220,11 @@ See also:
 -   With @ref Corrade/Utility/DebugStl.h not being included, @ref std::string
     instances could get accidentally printed as @ref ResourceKey instances.
     Added and explicit header dependency to avoid such cases.
+-   The @ref Magnum/Image.h, @ref Magnum/ImageView.h and
+    @ref Magnum/Trade/ImageData.h headers required
+    @ref Corrade/Containers/StridedArrayView.h to be included *before* in order
+    to use the @ref ImageView::pixels() "pixels()" function. Now it's enough
+    to just include it at any point, with no order dependency anymore.
 
 @subsection changelog-latest-deprecated Deprecated APIs
 

src/Magnum/Image.h

@@ -34,6 +34,17 @@
 #include "Magnum/DimensionTraits.h"
 #include "Magnum/PixelStorage.h"
 
+#ifndef DOXYGEN_GENERATING_OUTPUT
+namespace Corrade { namespace Containers {
+
+/* Forward declaration of an utility used in pixels() to avoid forcing users to
+   include the relatively large StridedArrayView header *before* the Image
+   class definition. */
+template<unsigned newDimensions, class U, unsigned dimensions, class T> StridedArrayView<newDimensions, U> arrayCast(const StridedArrayView<dimensions, T>& view);
+
+}}
+#endif
+
 namespace Magnum {
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
@@ -437,7 +448,8 @@ template<UnsignedInt dimensions> class Image {
          */
         template<class T> Containers::StridedArrayView<dimensions, T> pixels() {
             /* Deliberately not adding a StridedArrayView include, it should
-               work without since this is a templated function */
+               work without since this is a templated function and we declare
+               arrayCast() above to satisfy two-phase lookup. */
             return Containers::arrayCast<dimensions, T>(pixels());
         }
 

src/Magnum/ImageView.h

@@ -35,6 +35,17 @@
 #include "Magnum/PixelStorage.h"
 #include "Magnum/Math/Vector3.h"
 
+#ifndef DOXYGEN_GENERATING_OUTPUT
+namespace Corrade { namespace Containers {
+
+/* Forward declaration of an utility used in pixels() to avoid forcing users to
+   include the relatively large StridedArrayView header *before* the Image
+   class definition. */
+template<unsigned newDimensions, class U, unsigned dimensions, class T> StridedArrayView<newDimensions, U> arrayCast(const StridedArrayView<dimensions, T>& view);
+
+}}
+#endif
+
 namespace Magnum {
 
 /**
@@ -460,7 +471,8 @@ template<UnsignedInt dimensions, class T> class ImageView {
         template<class U> Containers::StridedArrayView<dimensions, typename std::conditional<std::is_const<Type>::value, typename std::add_const<U>::type, U>::type> pixels() const {
             if(!_data && !_data.size()) return {};
             /* Deliberately not adding a StridedArrayView include, it should
-               work without since this is a templated function */
+               work without since this is a templated function and we declare
+               arrayCast() above to satisfy two-phase lookup. */
             return Containers::arrayCast<dimensions, typename std::conditional<std::is_const<Type>::value, typename std::add_const<U>::type, U>::type>(pixels());
         }
 

src/Magnum/Test/ImageTest.cpp

@@ -24,7 +24,8 @@
 */
 
 /* Included as first to check that we *really* don't need the StridedArrayView
-   header for definition of pixels() */
+   header for definition of pixels(). We actually need, but just for the
+   arrayCast() template, which is forward-declared. */
 #include "Magnum/Image.h"
 
 #include <sstream>

src/Magnum/Test/ImageViewTest.cpp

@@ -24,7 +24,8 @@
 */
 
 /* Included as first to check that we *really* don't need the StridedArrayView
-   header for definition of pixels() */
+   header for definition of pixels(). We actually need, but just for the
+   arrayCast() template, which is forward-declared. */
 #include "Magnum/ImageView.h"
 
 #include <sstream>

src/Magnum/Trade/ImageData.h

@@ -36,6 +36,17 @@
 #include "Magnum/Trade/Trade.h"
 #include "Magnum/Trade/visibility.h"
 
+#ifndef DOXYGEN_GENERATING_OUTPUT
+namespace Corrade { namespace Containers {
+
+/* Forward declaration of an utility used in pixels() to avoid forcing users to
+   include the relatively large StridedArrayView header *before* the Image
+   class definition. */
+template<unsigned newDimensions, class U, unsigned dimensions, class T> StridedArrayView<newDimensions, U> arrayCast(const StridedArrayView<dimensions, T>& view);
+
+}}
+#endif
+
 namespace Magnum { namespace Trade {
 
 /**
@@ -417,7 +428,8 @@ template<UnsignedInt dimensions> class ImageData {
          */
         template<class T> Containers::StridedArrayView<dimensions, T> pixels() {
             /* Deliberately not adding a StridedArrayView include, it should
-               work without since this is a templated function */
+               work without since this is a templated function and we declare
+               arrayCast() above to satisfy two-phase lookup. */
             return Containers::arrayCast<dimensions, T>(pixels());
         }
 

src/Magnum/Trade/Test/ImageDataTest.cpp

@@ -24,7 +24,8 @@
 */
 
 /* Included as first to check that we *really* don't need the StridedArrayView
-   header for definition of pixels() */
+   header for definition of pixels(). We actually need, but just for the
+   arrayCast() template, which is forward-declared. */
 #include "Magnum/Trade/ImageData.h"
 
 #include <sstream>